Atmos. Meas. techniques

Tropospheric ozone column dataset from OMPS-LP/OMPS-NM limb–nadir matching
Andrea Orfanoz-Cheuquelaf, Carlo Arosio, Alexei Rozanov, Mark Weber, Annette Ladstätter-Weißenmayer, John P. Burrows, Anne M. Thompson, Ryan M. Stauffer, and Debra E. Kollonige
Atmos. Meas. Tech., 17, 1791–1809, https://doi.org/10.5194/amt-17-1791-2024, 2024
Valuable information on the tropospheric ozone column (TrOC) can be obtained globally by combining space-borne limb and nadir measurements (limb–nadir matching, LNM). This study describes the retrieval of TrOC from the OMPS instrument (since 2012) using the LNM technique. The OMPS-LNM TrOC was compared with ozonesondes and other satellite measurements, showing a good agreement with a negative bias within 1 to 4 DU. This new dataset is suitable for pollution studies.

Application of fuzzy c-means clustering for analysis of chemical ionization mass spectra: insights into the gas phase chemistry of NO3-initiated oxidation of isoprene
Rongrong Wu, Sören R. Zorn, Sungah Kang, Astrid Kiendler-Scharr, Andreas Wahner, and Thomas F. Mentel
Atmos. Meas. Tech., 17, 1811–1835, https://doi.org/10.5194/amt-17-1811-2024, 2024
Recent advances in high-resolution time-of-flight chemical ionization mass spectrometry (CIMS) enable the detection of highly oxygenated organic molecules, which efficiently contribute to secondary organic aerosol. Here we present an application of fuzzy c-means (FCM) clustering  to deconvolve CIMS data. FCM not only reduces the complexity of mass spectrometric data but also the chemical and kinetic information retrieved by clustering gives insights into the chemical processes involved.

Version 8 IMK/IAA MIPAS measurements of CFC-11, CFC-12, and HCFC-22
Gabriele P. Stiller, Thomas von Clarmann, Norbert Glatthor, Udo Grabowski, Sylvia Kellmann, Michael Kiefer, Alexandra Laeng, Andrea Linden, Bernd Funke, Maya García-Comas, and Manuel López-Puertas
Atmos. Meas. Tech., 17, 1759–1789, https://doi.org/10.5194/amt-17-1759-2024, 2024
CFC-11, CFC-12, and HCFC-22 contribute to the depletion of ozone and are potent greenhouse gases. They have been banned by the Montreal protocol. With MIPAS on Envisat the atmospheric composition could be observed between 2002 and 2012. We present here the retrieval of their atmospheric distributions for the final data version 8. We characterise the derived data by their error budget and their spatial resolution. An additional representation for direct comparison to models is also provided.

Gravity waves above the Northern Atlantic and Europe during streamer events using ADM-Aeolus
Sabine Wüst, Lisa Küchelbacher, Franziska Trinkl, and Michael Bittner
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-18,2024
Preprint under review for AMT (discussion: open, 0 comments)
Information about the energy of gravity waves (GWs) is crucial for improving atmosphere models. Most space-based studies report on the potential energy. We use ADM-Aeolus wind data to derive a lower limit of the kinetic energy density. However, the data quality is a challenge for such analyses, as the accuracy of the data is in the range of typical GW amplitudes. We find a temporal coincidence between enhanced or breaking planetary waves and enhanced gravity wave kinetic energy density.

A cloud-by-cloud approach for studying aerosol–cloud interaction in satellite observations
Fani Alexandri, Felix Müller, Goutam Choudhury, Peggy Achtert, Torsten Seelig, and Matthias Tesche
Atmos. Meas. Tech., 17, 1739–1757, https://doi.org/10.5194/amt-17-1739-2024, 2024
We present a novel method for studying aerosol–cloud interactions. It combines cloud-relevant aerosol concentrations from polar-orbiting lidar observations with the development of individual clouds from geostationary observations. Application to 1 year of data gives first results on the impact of aerosols on the concentration and size of cloud droplets and on cloud phase in the regime of heterogeneous ice formation. The method could enable the systematic investigation of warm and cold clouds.

CALOTRITON: a convective boundary layer height estimation algorithm from ultra-high-frequency (UHF) wind profiler data
Alban Philibert, Marie Lothon, Julien Amestoy, Pierre-Yves Meslin, Solène Derrien, Yannick Bezombes, Bernard Campistron, Fabienne Lohou, Antoine Vial, Guylaine Canut-Rocafort, Joachim Reuder, and Jennifer K. Brooke
Atmos. Meas. Tech., 17, 1679–1701, https://doi.org/10.5194/amt-17-1679-2024, 2024
We present a new algorithm, CALOTRITON, for the retrieval of the convective boundary layer depth with ultra-high-frequency radar measurements. CALOTRITON is partly based on the principle that the top of the convective boundary layer is associated with an inversion and a decrease in turbulence. It is evaluated using ceilometer and radiosonde data. It is able to qualify the complexity of the vertical structure of the low troposphere and detect internal or residual layers.

Lidar depolarization characterization using a reference system
Alkistis Papetta, Franco Marenco, Maria Kezoudi, Rodanthi-Elisavet Mamouri, Argyro Nisantzi, Holger Baars, Ioana Elisabeta Popovici, Philippe Goloub, Stéphane Victori, and Jean Sciare
Atmos. Meas. Tech., 17, 1721–1738, https://doi.org/10.5194/amt-17-1721-2024, 2024
We propose a method to determine depolarization parameters using observations from a reference instrument at a nearby location, needed for systems where a priori knowledge of cross-talk parameters is not available. It uses three-parameter equations to compare VDR between two co-located lidars at dust and molecular layers. It can be applied retrospectively to existing data acquired during campaigns. Its application to Cimel CE376 corrected VDR bias at high- and low-depolarizing layers.

Model-based evaluation of cloud geometry and droplet size retrievals from two-dimensional polarized measurements of specMACS
Lea Volkmer, Veronika Pörtge, Fabian Jakub, and Bernhard Mayer
Atmos. Meas. Tech., 17, 1703–1719, https://doi.org/10.5194/amt-17-1703-2024, 2024
Three-dimensional radiative transfer simulations are used to evaluate the performance of retrieval algorithms in the derivation of cloud geometry (cloud top heights) and cloud droplet size distributions from two-dimensional polarized radiance measurements of the airborne spectrometer of the Munich Aerosol Cloud Scanner. The cloud droplet size distributions are derived for the effective radius and variance. The simulations are based on cloud data from highly resolved large-eddy simulations.

Deriving the hygroscopicity of ambient particles using low-cost optical particle counters
Wei-Chieh Huang, Hui-Ming Hung, Ching-Wei Chu, Wei-Chun Hwang, and Shih-Chun Candice Lung
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-39,2024
Preprint under review for AMT (discussion: open, 0 comments)
This study investigates aerosol properties crucial for health, cloud formation, and climate impact. Employing a low-cost sensor system, we assess hygroscopicity of particulate matter (PM), the ability to influence cloud formation to improve the reported PM concentrations from low-cost sensors. The study introduces an alternate methodology for assessing aerosol hygroscopicity, offering insights into atmospheric science, air quality, and cloud dynamics.

3D wind observations with a compact mobile lidar based on tropo- and stratospheric aerosol backscatter
Thorben H. Mense, Josef Höffner, Gerd Baumgarten, Ronald Eixmann, Jan Froh, Alsu Mauer, Alexander Munk, Robin Wing, and Franz-Josef Lübken
Atmos. Meas. Tech., 17, 1665–1677, https://doi.org/10.5194/amt-17-1665-2024, 2024
A novel lidar system with five beams measured horizontal and vertical winds together, reaching altitudes up to 25 km. Developed in Germany, it revealed accurate horizontal wind data compared to forecasts, but vertical wind estimates differed. The lidar's capability to detect small-scale wind patterns was highlighted, advancing atmospheric research.

Assessment of current methane emission quantification techniques for natural gas midstream applications
Yunsong Liu, Jean-Daniel Paris, Gregoire Broquet, Violeta Bescós Roy, Tania Meixus Fernandez, Rasmus Andersen, Andrés Russu Berlanga, Emil Christensen, Yann Courtois, Sebastian Dominok, Corentin Dussenne, Travis Eckert, Andrew Finlayson, Aurora Fernández de la Fuente, Catlin Gunn, Ram Hashmonay, Juliano Grigoleto Hayashi, Jonathan Helmore, Soeren Honsel, Fabrizio Innocenti, Matti Irjala, Torgrim Log, Cristina Lopez, Francisco Cortés Martínez, Jonathan Martinez, Adrien Massardier, Helle Gottschalk Nygaard, Paula Agregan Reboredo, Elodie Rousset, Axel Scherello, Matthias Ulbricht, Damien Weidmann, Oliver Williams, Nigel Yarrow, Murès Zarea, Robert Ziegler, Jean Sciare, Mihalis Vrekoussis, and Philippe Bousquet
Atmos. Meas. Tech., 17, 1633–1649, https://doi.org/10.5194/amt-17-1633-2024, 2024
We investigated the performance of 10 methane emission quantification techniques in a blind controlled-release experiment at an inerted natural gas compressor station. We reported their respective strengths, weaknesses, and potential complementarity depending on the emission rates and atmospheric conditions. Additionally, we assess the dependence of emission quantification performance on key parameters such as wind speed, deployment constraints, and measurement duration.

Verification of parameterizations for clear sky downwelling longwave irradiance in the Arctic
Giandomenico Pace, Alcide di Sarra, Filippo Cali Quaglia, Virginia Ciardini, Tatiana Di Iorio, Antonio Iaccarino, Daniela Meloni, Giovanni Muscari, and Claudio Scarchilli
Atmos. Meas. Tech., 17, 1617–1632, https://doi.org/10.5194/amt-17-1617-2024, 2024
This study investigates the performances of 17 formulas to determine the clear sky longwave downward irradiance in the Arctic environment. The formulas need to be tuned to the environmental conditions of the studied region and, to date, few of them have been developed and/or tested in the Arctic. The best formulas provide biases and root mean squared errors respectively smaller than 1 and 5 W m-2. We intend to use these results to estimate the longwave cloud radiative perturbation.

Hybrid instrument network optimization for air quality monitoring
Nishant Ajnoti, Hemant Gehlot, and Sachchida Nand Tripathi
Atmos. Meas. Tech., 17, 1651–1664, https://doi.org/10.5194/amt-17-1651-2024, 2024
This research focuses on the optimal placement of hybrid instruments (sensors and monitors) to maximize satisfaction function considering population, PM2.5 concentration, budget, and other factors. Two algorithms are developed in this study: a genetic algorithm and a greedy algorithm. We tested these algorithms on various regions. The insights of this work aid in quantitative placement of air quality monitoring instruments in large cities, moving away from ad hoc approaches.

Shortwave Array Spectroradiometer-Hemispheric (SAS-He): Design and Evaluation
Evgueni Kassianov, Connor Flynn, James Barnard, Brian Ermold, and Jennifer Comstock
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-13,2024
Preprint under review for AMT (discussion: open, 0 comments)
Conventional ground-based radiometers commonly measure solar radiation at a few wavelengths within a narrow spectral range. These limitations prevent improved retrievals of aerosol, cloud, and surface characteristics. To address these limitations, an advanced ground-based radiometer with expanded spectral coverage and hyperspectral capability is introduced. Its good performance is demonstrated using reference data collected over three coastal regions with diverse types of aerosols and clouds.

First validation of high-resolution satellite-derived methane emissions from an active gas leak in the UK
Emily Dowd, Alistair J. Manning, Bryn Orth-Lashley, Marianne Girard, James France, Rebecca E. Fisher, Dave Lowry, Mathias Lanoisellé, Joseph R. Pitt, Kieran M. Stanley, Simon O'Doherty, Dickon Young, Glen Thistlethwaite, Martyn P. Chipperfield, Emanuel Gloor, and Chris Wilson
Atmos. Meas. Tech., 17, 1599–1615, https://doi.org/10.5194/amt-17-1599-2024, 2024
We provide the first validation of the satellite-derived emission estimates using surface-based mobile greenhouse gas surveys of an active gas leak detected near Cheltenham, UK. GHGSat’s emission estimates broadly agree with the surface-based mobile survey and steps were taken to fix the leak, highlighting the importance of satellite data in identifying emissions and helping to reduce our human impact on climate change.

Lower-cost eddy covariance for CO2 and H2O fluxes over grassland and agroforestry
Justus G. V. van Ramshorst, Alexander Knohl, José Ángel Callejas-Rodelas, Robert Clement, Timothy C. Hill, Lukas Siebicke, and Christian Markwitz
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-30,2024
Preprint under review for AMT (discussion: open, 0 comments)
In this work we present experimental field results of a lower-cost eddy covariance (LC-EC) system, which can measure the ecosystem exchange of carbon dioxide and water vapour with the atmosphere. During three field campaigns on a grassland and agroforestry grassland we compared the LC-EC with a conventional eddy covariance (CON-EC) system. Our results show that LC-EC has the potential to measure EC fluxes for only approximately 25 % of the costs of a CON-EC system.

In situ observations of supercooled liquid water clouds over Dome C, Antarctica by balloon-borne sondes
Philippe Ricaud, Pierre Durand, Paolo Grigioni, Massimo Del Guasta, Giuseppe Camporeale, Axel Roy, Jean-Luc Attié, and John Bognar
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-8,2024
Preprint under review for AMT (discussion: open, 0 comments)
Clouds in Antarctica are key elements affecting climate evolution. Some clouds are constituted of supercooled liquid water (SLW, water held in liquid form below 0 °C) and are difficult to forecast by models. We performed in-situ observations of SLW clouds at Concordia station using SLW sondes attached to meteorological balloons in summer 2021–2022. The SLW clouds were observed in a saturated layer at the top of the Planetary Boundary Layer in agreement with ground-based LIDAR observations.

Enhancing consistency of microphysical properties of precipitation across the melting layer in dual-frequency precipitation radar data
Kamil Mroz, Alessandro Battaglia, and Ann M. Fridlind
Atmos. Meas. Tech., 17, 1577–1597, https://doi.org/10.5194/amt-17-1577-2024, 2024
In this study, we examine the extent to which radar measurements from space can inform us about the properties of clouds and precipitation. Surprisingly, our analysis showed that the amount of ice turning into rain was lower than expected in the current product. To improve on this, we came up with a new way to extract information about the size and concentration of particles from radar data. As long as we use this method in the right conditions, we can even estimate how dense the ice is.

A novel infrared imager for studies of hydroxyl and oxygen nightglow emissions in the mesopause above northern Scandinavia
Peter Dalin, Urban Brändström, Johan Kero, Peter Voelger, Takanori Nishiyama, Trond Trondsen, Devin Wyatt, Craig Unick, Vladimir Perminov, Nikolay Pertsev, and Jonas Hedin
Atmos. Meas. Tech., 17, 1561–1576, https://doi.org/10.5194/amt-17-1561-2024, 2024
A novel infrared imaging instrument (OH imager) was put into operation in November 2022 at the Swedish Institute of Space Physics in Kiruna (Sweden). The OH imager is dedicated to the study of nightglow emissions coming from the hydroxyl (OH) and molecular oxygen (O2) layers in the mesopause (80–100 km). Based on a brightness ratio of two OH emission lines, the neutral temperature is estimated at around 87 km. The average daily winter temperature for the period January–April 2023 is 203±10 K.

Optimization of a direct detection UV wind lidar architecture for 3D wind reconstruction at high altitude
Thibault Boulant, Tomline Michel, and Matthieu Valla
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-41,2024
Preprint under review for AMT (discussion: open, 0 comments)
This paper presents a design of a UV wind lidar, made with a UV fiber laser and a Quadri Mach-Zehnder interferometer as a spectral analyzer, used to measure the wind in front of future low consumption aircraft. The article details the optimization of the different elements of the instrument with simulations. This paper also presents a method to optimize laser angles for determining wind direction and strength, and shows a 50 % improvement over the current angles used.